105 DMU 2 decoders

[liamsantini]

Hi everyone. I’d like to know why after installing two decoders in my Bachmann 105 when I go forward both the headlights and rear lights are white and when I go backwards the headlights are red and rear lights are red? When I put it on DC the directional lights work properly again. Forwards white and rear red, backwards white and rear red. Am I doing something wrong? The decoder in the motor carriage is Laise, and the decoder in the rear carriage is Hornby.

[Stevelewis]

Try  reversing  the  decoder in  the  unpowered  car 

 

( I e turn  the  actual decoder  around in the  socket)

 

It is  also possible  to  alter  the  value  of CV29  to make  the  decoder  'think' it  is  travelling  the  other  way

[Ray H]

I found that I had to put both cars on the programming track and configure the trailer first. I could then remove the trailer and configure the powered coach on its own which involves changing the direction it sees compared to the trailer. 

[Phil S]

There is 1 particular Bachmann DMU I have come across ( a friend's, and I cannot recall which apart from it having 2 decoders - possibly the same  ( release period) as the Kings-Cross destination model  which I think was a 105?)  in which the 'factory' had modified the tracks on the trailing car PCB because it had been designed / labelled the wrong way round  (which places the +ve blue common connection where the green function wired would be and vice versa)

If you do have the modified board - ignore the etched labelling in favour of the handwritten (I think it was done with a felt pen) - if in doubt email Bachmann Service for clarification .. they may have done the mod!

[liamsantini]

Just tried that Ray, no luck. Could I set them to different addresses? One 6 and one 7? If I change the CV29 value, what do I change it to?

[warringtonbankquay]

There is an anomaly on the circuit board on (some?) Bachmann Class 105s.

 

Pin 1 and Pin 8 are incorrectly wired and/or labelled from memory and you may find that this is affecting the lights.

 

Turning the decoder plug through 180 degrees worked for me.

 

Chris

[liamsantini]

All sorted chaps. Changed CV 29 and it now works. Thank you guys, much appreciated

[SRman]

If the lights are already working, turning the decoder 180 degrees will probably not work - it will probably show no lights after that.

The decoder in the trailing car needs to have CV 29 value read then altered: if it is an even number, add 1; if it is an odd number, subtract 1.

[liamsantini]

Thank you all for your kind help. Much appreciated. It’s working good now